The App Store, even with 25,000 applications, is still a new market and one we're all, developers, users, and media alike, trying to figure out. Developer James Thomson recently did an experiment to see how Twitkitteh, a fun little app, would compare in terms of sales and earnings, to his acclaimed PCalc in the App Store.

The results? Thomson talks about them in a blog post entitled Where Did it All Go Wrong?

Since Twitkitteh released about a week ago, we have sold exactly a hundred and one copies, at roughly 99c each. That makes it about £50 in terms of income at current exchange rates after Apple’s 30% cut. About 14 quid of that went on the domain name for a year, and about another 11 quid on hosting the domain on our existing server.

That leaves us £25 profit for three week’s work. Oh, and minus the 120 or so engineer-hours spent designing, writing, and promoting it that could have been spent on something else. So, depending on exactly how much you rate iPhone engineers at on an hourly basis, you can calculate exactly how much we lost on the whole project.

The good news is, with his grand Twitkitteh experiment completed (for now?), PCalc and PCalc Lite have received updates:

PCalc [iTunes link] gets a brand new engineering layout, with hyperbolic trig functions, hypotenuse, leg, gamma, delta percent and more. You also get a classic theme taken from PCalc on Mac OS X, and six new key click sounds you can choose from too.

PCalc Lite [iTunes link] gets just two of the click sounds, and some other small improvements. PCalc Lite remains completely free however, and completely awesome. If you want to get a feel for how the full PCalc works on the iPhone, just try it out.

Here's hoping quality apps like PCalc and others will sell well enough that developers won't have to spend their limited time working on the next great fart app to makes ends meet.

Thanks to James Thomson at Twitkitteh [iTunes link] for helping our awesome readers help their amazing cats express their inner lulz on the Twitter. James was gracious enough to pass along two iTunes App Store Promo Codes for Twitkitteh to two lucky TiPb readers, and without further ado, those are:

• Stephanie Berry
• bas.o

Enjoy. And make sure your kitteh's follow @twitkitteh and @theiphoneblog, b'okay?